Alien Blue, had a 5s for almost 2 months and is still the only app I paid for. You don't have to upgrade to the 'Pro Version' for the app to be awesome either (You can't submit new self posts without pro, you can still comment on other posts though). I upgraded as more of a donation / thank you for making a nice Reddit client more than anything!

iTV Shows to notify me when one of my shows is about to come on.

Quiz Up for a very fun game you play against other people with tons of topics to choose from.